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arXiv 1710.09552cs.CV
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可分离非局部均值的降阶

Artifact reduction for separable non-local means

Indian Institute of Science(印度科学研究所)

Sanjay Ghosh, Kunal N. Chaudhury

摘要:

最近证明[J. Electron. Imaging,25(2),2016],可以使用称为提升的方法对一维信号执行快速非局部均值(NLM)去噪。提升的代价与补丁的长度无关,这大大减少了大补丁的运行时间。不幸的是,很难直接扩展提升图像的非局部均值去噪。为了绕过这一点,作者提出了一种可分离的近似,其中使用提升过滤图像的行和列。整体算法明显快于NLM,并且结果在PSNR方面相当。然而,可分离处理经常在图像中产生垂直和水平条纹。这个问题以前通过使用基于双边滤波器的后平滑来解决,这在去除一些条纹方面是有效的。在这封信中,我们证明,条纹可以减轻摆在首位,简单地涉及相邻的行(或列)的过滤。换句话说,我们使用二维搜索(类似于NLM),同时仍然使用一维补丁(如前所述)。新颖之处在于观察到可以使用提升来执行二维搜索。所提出的方法生成无伪影的图像,其质量和PSNR与NLM相当,同时速度明显更快。

英文摘要:

It was recently demonstrated [J. Electron. Imaging, 25(2), 2016] that one can perform fast non-local means (NLM) denoising of one-dimensional signals using a method called lifting. The cost of lifting is independent of the patch length, which dramatically reduces the run-time for large patches. Unfortunately, it is difficult to directly extend lifting for non-local means denoising of images. To bypass this, the authors proposed a separable approximation in which the image rows and columns are filtered using lifting. The overall algorithm is significantly faster than NLM, and the results are comparable in terms of PSNR. However, the separable processing often produces vertical and horizontal stripes in the image. This problem was previously addressed by using a bilateral filter-based post-smoothing, which was effective in removing some of the stripes. In this letter, we demonstrate that stripes can be mitigated in the first place simply by involving the neighboring rows (or columns) in the filtering. In other words, we use a two-dimensional search (similar to NLM), while still using one-dimensional patches (as in the previous proposal). The novelty is in the observation that one can use lifting for performing two-dimensional searches. The proposed approach produces artifact-free images, whose quality and PSNR are comparable to NLM, while being significantly faster.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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